Standard Tapers

906 STANDARD TAPERS

STANDARD TAPERS Standard Tapers Certain types of small tools and machine parts, such as twist drills, end mills, arbors, lathe centers, etc., are provided with taper shanks which fit into spindles or sockets of cor- responding taper, thus providing not only accurate alignment between the tool or other part and its supporting member, but also more or less frictional resistance for driving the tool. There are several standards for “self-holding” tapers, but the American National, Morse, and the Brown & Sharpe are the standards most widely used by American manufacturers. The name self-holding has been applied to the smaller tapers—like the Morse and the Brown & Sharpe—because, where the angle of the taper is only 2 or 3 degrees, the shank of a tool is so firmly seated in its socket that there is considerable frictional resistance to any force tending to turn or rotate the tool relative to the socket. The term “self-holding” is used to distinguish relatively small tapers from the larger or self-releasing type. A milling 1⁄ machine spindle having a taper of 3 2 inches per foot is an example of a self-releasing taper. The included angle in this case is over 16 degrees and the tool or arbor requires a pos- itive locking device to prevent slipping, but the shank may be released or removed more readily than one having a smaller taper of the self-holding type. Morse Taper.—Dimensions relating to Morse standard taper shanks and sockets may be found in an accompanying table. The taper for different numbers of Morse tapers is slightly 5⁄ different, but it is approximately 8 inch per foot in most cases. The table gives the actual tapers, accurate to five decimal places. Morse taper shanks are used on a variety of tools, and exclusively on the shanks of twist drills. Dimensions for Morse Stub Taper Shanks are given in Table 1a. Brown & Sharpe Taper.—This standard taper is used for taper shanks on tools such as 1⁄ end mills and reamers, the taper being approximately 2 inch per foot for all sizes except for taper No. 10, where the taper is 0.5161 inch per foot. Brown & Sharpe taper sockets are used for many arbors, collets, and machine tool spindles, especially milling machines and grinding machines. In many cases there are a number of different lengths of sockets corre- sponding to the same number of taper; all these tapers, however, are of the same diameter at the small end. Jarno Taper.—The Jarno taper was originally proposed by Oscar J. Beale of the Brown & Sharpe Mfg. Co. This taper is based on such simple formulas that practically no calcula- tions are required when the number of taper is known. The taper per foot of all Jarno taper sizes is 0.600 inch on the diameter. The diameter at the large end is as many eighths, the diameter at the small end is as many tenths, and the length as many half inches as are indi- 7⁄ cated by the number of the taper. For example, a No. 7 Jarno taper is 8 inch in diameter at 7⁄ 7⁄ 1⁄ the large end; 10 , or 0.700 inch at the small end; and 2 , or 3 2 inches long; hence, diameter at large end = No. of taper ÷ 8; diameter at small end = No. of taper ÷ 10; length of taper = No. of taper ÷ 2. The Jarno taper is used on various machine tools, especially profiling machines and die-sinking machines. It has also been used for the headstock and tailstock spindles of some lathes. American National Standard Machine Tapers: This standard includes a self-holding series (Tables 2, 3, 4, 5 and 7a) and a steep taper series, Table 6. The self-holding taper series consists of 22 sizes which are listed in Table 7a. The reference gage for the self-holding tapers is a plug gage. Table 7b gives the dimensions and tolerances for both plug and ring gages applying to this series. Tables 2 through 5 inclusive give the dimensions for self- holding taper shanks and sockets which are classified as to (1) means of transmitting torque from spindle to the tool shank, and (2) means of retaining the shank in the socket. The steep machine tapers consist of a preferred series (bold-face type, Table 6) and an intermediate series (light-face type). A self-holding taper is defined as “a taper with an STANDARD TAPERS 907 angle small enough to hold a shank in place ordinarily by friction without holding means. (Sometimes referred to as slow taper.)” A steep taper is defined as “a taper having an angle sufficiently large to insure the easy or self-releasing feature.” The term “gage line” indi- cates the basic diameter at or near the large end of the taper. Table 1a. Morse Stub Taper Shanks

Shank Tang Small End of Dia. Taper Taper End of No. Plug, b Total per per a of D Socket, Length, Depth, Thickness, Length, Taper Foota Inchb A B C E F

5⁄ 1⁄ 13⁄ 5⁄ 1 0.59858 0.049882 0.4314 0.475 1 16 18 64 16

11⁄ 7⁄ 19⁄ 7⁄ 2 0.59941 0.049951 0.6469 0.700 1 16 116 64 16

3⁄ 25⁄ 9⁄ 3 0.60235 0.050196 0.8753 0.938 2 1 4 64 16

3⁄ 1⁄ 33⁄ 11⁄ 4 0.62326 0.051938 1.1563 1.231 2 8 216 64 16

11⁄ 3⁄ 15⁄ 5 0.63151 0.052626 1.6526 1.748 3 2 16 4 16

Tang Socket Tang Slot

Min. Depth of Socket Tapered Hole End to No. Radius Tang Slot, of of Mill, Diameter, Plug Depth, Drilled Reamed Width, Length, M Taper G H P X Y N O

3⁄ 13⁄ 7⁄ 5⁄ 29⁄ 25⁄ 7⁄ 23⁄ 1 16 32 8 16 32 32 32 32

7⁄ 39⁄ 1⁄ 5⁄ 7⁄ 15⁄ 5⁄ 15⁄ 2 32 64 116 132 164 16 16 16

9⁄ 13⁄ 1⁄ 3⁄ 5⁄ 1⁄ 13⁄ 1⁄ 3 32 16 14 18 116 116 32 18

3⁄ 3⁄ 7⁄ 9⁄ 1⁄ 3⁄ 17⁄ 3⁄ 4 8 132 116 116 12 116 32 18

9⁄ 19⁄ 13⁄ 15⁄ 7⁄ 7⁄ 25⁄ 3⁄ 5 16 132 116 116 18 116 32 14

a These are basic dimensions. b These dimensions are calculated for reference only. All dimensions in inches. 3⁄ 1⁄ 5⁄ 3⁄ 1⁄ Radius J is 64 , 16 , 64 , 32 , and 8 inch respectively for Nos. 1, 2, 3, 4, and 5 tapers. 908 STANDARD TAPERS

Table 1b. Morse Standard Taper Shanks

Small Diameter Shank End of End of Depth No. of Taper Taper Plug Socket Length Depth of Hole Taper per Foot per Inch D A B S H 11⁄ 7⁄ 1⁄ 0 0.62460 0.05205 0.252 0.3561 2 32 232 232

9⁄ 7⁄ 5⁄ 1 0.59858 0.04988 0.369 0.475 2 16 216 232

1⁄ 15⁄ 39⁄ 2 0.59941 0.04995 0.572 0.700 3 8 216 264

7⁄ 11⁄ 1⁄ 3 0.60235 0.05019 0.778 0.938 3 8 316 34

7⁄ 5⁄ 1⁄ 4 0.62326 0.05193 1.020 1.231 4 8 48 48

1⁄ 7⁄ 1⁄ 5 0.63151 0.05262 1.475 1.748 6 8 58 54

9⁄ 1⁄ 21⁄ 6 0.62565 0.05213 2.116 2.494 8 16 84 764

5⁄ 1⁄ 5⁄ 7 0.62400 0.05200 2.750 3.270 11 8 114 1064 Tang or Tongue Keyway Plug Keyway Depth Thickness Length Radius Width Length to End P t T R Dia. W L K

1⁄ 5⁄ 11⁄ 9⁄ 15⁄ 2 0.1562 4 32 0.235 64 16 116

1⁄ 3⁄ 3⁄ 3⁄ 1⁄ 2 8 0.2031 8 16 0.343 0.218 4 216

9⁄ 7⁄ 1⁄ 17⁄ 7⁄ 1⁄ 2 16 0.2500 16 4 32 0.266 8 22

3⁄ 9⁄ 9⁄ 23⁄ 3⁄ 1⁄ 3 16 0.3125 16 32 32 0.328 1 16 316

1⁄ 5⁄ 5⁄ 31⁄ 1⁄ 7⁄ 4 16 0.4687 8 16 32 0.484 1 4 38

3⁄ 3⁄ 3⁄ 13⁄ 1⁄ 15⁄ 5 16 0.6250 4 8 132 0.656 1 2 416

1⁄ 1⁄ 1⁄ 3⁄ 7 4 0.7500 1 8 2 2 0.781 1 4 7

3⁄ 3⁄ 5⁄ 5⁄ 1⁄ 10 1.1250 1 8 4 28 1.156 2 8 92 STANDARD TAPERS 909

Table 2. American National Standard Taper Drive with Tang, Self-Holding Tapers ANSI/ASME B5.10-1994

Shank Tang Diameter Total Gage Line No. at Gage Length to End Radius of Line (1) of Shank of Shank Thickness Length of Mill Diameter Taper A B C E F G H 0.239 0.23922 1.28 1.19 0.125 0.19 0.19 0.18 0.299 0.29968 1.59 1.50 0.156 0.25 0.19 0.22 0.375 0.37525 1.97 1.88 0.188 0.31 0.19 0.28 1 0.47500 2.56 2.44 0.203 0.38 0.19 0.34 2 0.70000 3.13 2.94 0.250 0.44 0.25 0.53 3 0.93800 3.88 3.69 0.312 0.56 0.22 0.72 4 1.23100 4.88 4.63 0.469 0.63 0.31 0.97 1⁄ 4 2 1.50000 5.38 5.13 0.562 0.69 0.38 1.20 5 1.74800 6.12 5.88 0.625 0.75 0.38 1.41 6 2.49400 8.25 8.25 0.750 1.13 0.50 2.00 Socket Tang Slot Min. Depth of Hole Gage Line Shank End No. K to to Back of of Radius Tang Slot Width Length Tang Slot Taper J Drilled Reamed M N O P 0.239 0.03 1.06 1.00 0.94 0.141 0.38 0.13 0.299 0.03 1.31 1.25 1.17 0.172 0.50 0.17 0.375 0.05 1.63 1.56 1.47 0.203 0.63 0.22 1 0.05 2.19 2.16 2.06 0.218 0.75 0.38 2 0.06 2.66 2.61 2.50 0.266 0.88 0.44 3 0.08 3.31 3.25 3.06 0.328 1.19 0.56 4 0.09 4.19 4.13 3.88 0.484 1.25 0.50 1⁄ 4 2 0.13 4.62 4.56 4.31 0.578 1.38 0.56 5 0.13 5.31 5.25 4.94 0.656 1.50 0.56 6 0.16 7.41 7.33 7.00 0.781 1.75 0.50 All dimensions are in inches. (1) See Table 7b for plug and ring gage dimensions. Tolerances: For shank diameter A at gage line, + 0.002 − 0.000; for hole diameter A, + 0.000 − 0.002. For tang thickness E up to No. 5 inclusive, + 0.000 − 0.006; No. 6, + 0.000 − 0.008. For width N of tang slot up to No. 5 inclusive, + 0.006; − 0.000; No. 6, + 0.008 − 0.000. For centrality of tang E with center line of taper, 0.0025 (0.005 total indicator variation). These centrality tolerances also apply to the tang slot N. On rate of taper, all sizes 0.002 per foot. This tolerance may be applied on shanks only in the direction which increases the rate of taper and on sockets only in the direction which decreases the rate of taper. Tolerances for two-decimal dimensions are plus or minus 0.010, unless otherwise specified. 910 STANDARD TAPERS

Table 3. American National Standard Taper Drive with Keeper Key Slot, Self-Holding Tapers ANSI/ASME B5.10-1994

Shank Tang Socket Dia. at Gage Min. Depth Gage Gage Line Radius of Hole Line to No. Line Total to of K Tang of (1) Length End Thickness Length Mill Diameter Radius Slot Taper A B C E F G H J Drill Ream M 3 0.938 3.88 3.69 0.312 0.56 0.28 0.78 0.08 3.31 3.25 3.06 4 1.231 4.88 4.63 0.469 0.63 0.31 0.97 0.09 4.19 4.13 3.88

1⁄ 4 2 1.500 5.38 5.13 0.562 0.69 0.38 1.20 0.13 4.63 4.56 4.32 5 1.748 6.13 5.88 0.625 0.75 0.38 1.41 0.13 5.31 5.25 4.94 6 2.494 8.56 8.25 0.750 1.13 0.50 2.00 0.16 7.41 7.33 7.00 7 3.270 11.63 11.25 1.125 1.38 0.75 2.63 0.19 10.16 10.08 9.50

Tang Slot Keeper Slot in Shank Keeper Slot in Socket

Gage Shank End Gage Line Line to No. to Back of to Bottom Front of Width Length Slot of Slot Length Width of Slot Length Width Taper N O P Y′ X N′ Y Z N′ 3 0.328 1.19 0.56 1.03 1.13 0.266 1.13 1.19 0.266

4 0.484 1.25 0.50 1.41 1.19 0.391 1.50 1.25 0.391

1⁄ 4 2 0.578 1.38 0.56 1.72 1.25 0.453 1.81 1.38 0.453

5 0.656 1.50 0.56 2.00 1.38 0.516 2.13 1.50 0.516

6 0.781 1.75 0.50 2.13 1.63 0.641 2.25 1.75 0.641

7 1.156 2.63 0.88 2.50 1.69 0.766 2.63 1.81 0.766 All dimensions are in inches. (1) See Table 7b for plug and ring gage dimensions. Tolerances: For shank diameter A at gage line, +0.002, −0; for hole diameter A, +0, −0.002. For tang thickness E up to No. 5 inclusive, +0, −0.006; larger than No. 5, +0, −0.008. For width of slots N and N′ up to No. 5 inclusive, +0.006, −0; larger than No. 5, +0.008, −0. For centrality of tang E with center line of taper 0.0025 (0.005 total indicator variation). These centrality tolerances also apply to slots N and N′. On rate of taper, see footnote in Table 2. Tolerances for two-decimal dimensions are ±0.010 unless otherwise specified. STANDARD TAPERS 911

Table 4. American National Standard Nose Key Drive with Keeper Key Slot, Self-Holding Tapers ANSI/ASME B5.10-1994

Taper A(1) B′ CQI′ IRS 200 2.000 5.13 0.25 1.38 1.63 1.010 0.562 250 2.500 5.88 0.25 1.38 2.06 1.010 0.562 300 3.000 6.63Min 0.25 1.63 2.50 2.010 0.562 350 3.500 7.440.003 0.31 2.00 2.94 2.010 0.562 400 4.000 8.19Max 0.31 2.13 3.31 2.010 0.562 450 4.500 9.000.035 0.38 2.38 3.81 3.010 0.812 500 5.000 9.75for 0.38 2.50 4.25 3.010 0.812 600 6.000 11.31all 0.44 3.00 5.19 3.010 0.812 800 8.000 14.38sizes 0.50 3.50 7.00 4.010 1.062 1000 10.000 17.44 0.63 4.50 8.75 4.010 1.062 1200 12.000 20.50 0.75 5.38 10.50 4.010 1.062 Taper DD′a WXN′ R′ S′ T 200 1.41 0.375 3.44 1.56 0.656 1.000 0.50 4.75 250 1.66 0.375 3.69 1.56 0.781 1.000 0.50 5.50 300 2.25 0.375 4.06 1.56 1.031 2.000 0.50 6.25 350 2.50 0.375 4.88 2.00 1.031 2.000 0.50 6.94 400 2.75 0.375 5.31 2.25 1.031 2.000 0.50 7.69 450 3.00 0.500 5.88 2.44 1.031 3.000 0.75 8.38 500 3.25 0.500 6.44 2.63 1.031 3.000 0.75 9.13 600 3.75 0.500 7.44 3.00 1.281 3.000 0.75 10.56 800 4.75 0.500 9.56 4.00 1.781 4.000 1.00 13.50 1000 ……11.50 4.75 2.031 4.000 1.00 16.31 1200 ……13.75 5.75 2.031 4.000 1.00 19.00 Taper UVMNOP Y Z 200 1.81 1.00 4.50 0.656 1.56 0.94 2.00 1.69 250 2.25 1.00 5.19 0.781 1.94 1.25 2.25 1.69 300 2.75 1.00 5.94 1.031 2.19 1.50 2.63 1.69 350 3.19 1.25 6.75 1.031 2.19 1.50 3.00 2.13 400 3.63 1.25 7.50 1.031 2.19 1.50 3.25 2.38 450 4.19 1.50 8.00 1.031 2.75 1.75 3.63 2.56 500 4.63 1.50 8.75 1.031 2.75 1.75 4.00 2.75 600 5.50 1.75 10.13 1.281 3.25 2.06 4.63 3.25 800 7.38 2.00 12.88 1.781 4.25 2.75 5.75 4.25 1000 9.19 2.50 15.75 2.031 5.00 3.31 7.00 5.00 1200 11.00 3.00 18.50 2.531 6.00 4.00 8.25 6.00 a Thread is UNF-2B for hole; UNF-2A for screw. (1) See Table 7b for plug and ring gage dimensions. All dimensions are in inches. AE is 0.005 greater than one-half of A. Width of drive key R″ is 0.001 less than width R″ of keyway. Tolerances: For diameter A of hole at gage line, +0, −0.002; for diameter A of shank at gage line, +0.002, −0; for width of slots N and N′, +0.008, −0; for width of drive keyway R′ in socket, +0, − 0.001; for width of drive keyway R in shank, 0.010, −0; for centrality of slots N and N′ with center line of spindle, 0.007; for centrality of keyway with spindle center line: for R, 0.004 and for R′, 0.002 T.I.V. On rate of taper, see footnote in Table 2. Two-decimal dimensions, ±0.010 unless otherwise specified. 912 STANDARD TAPERS

Table 5. American National Standard Nose Key Drive with Drawbolt, Self-Holding Tapers ANSI/ASME B5.10-1994

Sockets Drive Key Drive Keyway Dia. Dia. Screw Holes Gage of at Center Line UNF 2B Line to Dia. Depth Draw No. Gage to Center Hole UNF Front of of of Bolt of Line of Screw 2A Screw Width Width Depth Relief Relief Relief Hole Taper Aa D D′ R″ R′ S′ T U V d 200 2.000 1.41 0.38 0.999 1.000 0.50 4.75 1.81 1.00 1.00 250 2.500 1.66 0.38 0.999 1.000 0.50 5.50 2.25 1.00 1.00 300 3.000 2.25 0.38 1.999 2.000 0.50 6.25 2.75 1.00 1.13 350 3.500 2.50 0.38 1.999 2.000 0.50 6.94 3.19 1.25 1.13 400 4.000 2.75 0.38 1.999 2.000 0.50 7.69 3.63 1.25 1.63 450 4.500 3.00 0.50 2.999 3.000 0.75 8.38 4.19 1.50 1.63 500 5.000 3.25 0.50 2.999 3.000 0.75 9.13 4.63 1.50 1.63 600 6.000 3.75 0.50 2.999 3.000 0.75 10.56 5.50 1.75 2.25 800 8.000 4.75 0.50 3.999 4.000 1.00 13.50 7.38 2.00 2.25 1000 10.000 ……3.999 4.000 1.00 16.31 9.19 2.50 2.25 1200 12.000 ……3.999 4.000 1.00 19.00 11.00 3.00 2.25 a See Table 7b for plug and ring gage dimensions. Shanks Drawbar Hole Drive Keyway Center Dia. Gage Length Depth Depth Line to of Line to from of of Depth Bottom Counter First No. Gage Dia. Drilled Thread of 60° of Bore Thread of Line UNC-2B Hole AP Chamfer Width Depth Keyway G AO Taper B′ AL E J R S AE 7⁄ 200 5.13 8 –9 2.44 1.75 0.91 4.78 0.13 1.010 0.562 1.005 7⁄ 250 5.88 8 –9 2.44 1.75 0.91 5.53 0.13 1.010 0.562 1.255 300 6.63 1–8 2.75 2.00 1.03 6.19 0.19 2.010 0.562 1.505 350 7.44 1–8 2.75 2.00 1.03 7.00 0.19 2.010 0.562 1.755 1⁄ 400 8.19 1 2 –6 4.00 3.00 1.53 7.50 0.31 2.010 0.562 2.005 1⁄ 450 9.00 1 2 –6 4.00 3.00 1.53 8.31 0.31 3.010 0.812 2.255 1⁄ 500 9.75 1 2 –6 4.00 3.00 1.53 9.06 0.31 3.010 0.812 2.505 1⁄ 600 11.31 2–4 2 5.31 4.00 2.03 10.38 0.50 3.010 0.812 3.005 1⁄ 800 14.38 2–4 2 5.31 4.00 2.03 13.44 0.50 4.010 1.062 4.005 1⁄ 1000 17.44 2–4 2 5.31 4.00 2.03 16.50 0.50 4.010 1.062 5.005 1⁄ 1200 20.50 2–4 2 5.31 4.00 2.03 19.56 0.50 4.010 1.062 6.005 All dimensions in inches. Exposed length C is 0.003 minimum and 0.035 maximum for all sizes. ′ 3⁄ 1⁄ Drive Key D screw sizes are 8 –24 UNF-2A up to taper No. 400 inclusive and 2 –20 UNF-2A for larger tapers. Tolerances: For diameter A of hole at gage line, +0.000, −0.002 for all sizes; for diameter A of shank at gage line, +0.002, −0.000; for all sizes; for width of drive keyway R′ in socket, +0.000, − 0.001; for width of drive keyway R in shank, +0.010, −0.000; for centrality of drive keyway R′, with center line of shank, 0.004 total indicator variation, and for drive keyway R′, with center line of spindle, 0.002. On rate of taper, see footnote in Table 2. Tolerances for two-decimal dimensions are ±0.010 unless otherwise specified. STANDARD TAPERS 913

Table 6. ANSI Standard Steep Machine Tapers ANSI/ASME B5.10-1994 Dia. Taper at Length Taper Dia.at Length No. of per Gage Along No. of per Gage Along Taper Foota Lineb Axis Taper Foota Lineb Axis 5 3.500 0.500 0.6875 35 3.500 1.500 2.2500 10 3.500 0.625 0.8750 40 3.500 1.750 2.5625 15 3.500 0.750 1.0625 45 3.500 2.250 3.3125 20 3.500 0.875 1.3125 50 3.500 2.750 4.0000 25 3.500 1.000 1.5625 55 3.500 3.500 5.1875 30 3.500 1.250 1.8750 60 3.500 4.250 6.3750 a This taper corresponds to an included angle of 16°, 35′, 39.4″. b The basic diameter at gage line is at large end of taper. All dimensions given in inches. The tapers numbered 10, 20, 30, 40, 50, and 60 that are printed in heavy-faced type are designated as the “Preferred Series.” The tapers numbered 5, 15, 25, 35, 45, and 55 that are printed in light-faced type are designated as the “Intermediate Series.” Table 7a. American National Standard Self-holding Tapers — Basic Dimensions ANSI/ASME B5.10-1994 Dia.at No. Taper Gage Origin of per Linea Means of of Taper Foot A Driving and Holdinga Series .239 0.50200 0.23922 .299 0.50200 0.29968 Tang Drive With Shank Held in by Friction .375 0.50200 0.37525 Brown & (See Table 2) Sharpe Taper 1 0.59858 0.47500 Series 2 0.59941 0.70000 3 0.60235 0.93800 4 0.62326 1.23100 1⁄ 4 2 0.62400 1.50000 Tang Drive With Shank Held in by Key Morse 5 0.63151 1.74800 (See Table 3) Taper Series 6 0.62565 2.49400 7 0.62400 3.27000 200 0.750 2.000 Key Drive With Shank Held in by Key (See Table 4) 250 0.750 2.500 300 0.750 3.000 350 0.750 3.500 3⁄ Inch 400 0.750 4.000 4 per 450 0.750 4.500 Key Drive With Shank Heldin by Draw-bolt Foot 500 0.750 5.000 (See Table 5) Taper Series 600 0.750 6.000 800 0.750 8.000 1000 0.750 10.000 1200 0.750 12.000 a See illustrations above Tables 2 through 5. All dimensions given in inches. 914 STANDARD TAPERS

Table 7b. American National Standard Plug and Ring Gages for the Self-Holding Taper Series ANSI/ASME B5.10-1994

b Depth of Tolerances for Diameter A Diameter at Length Diameteraat Gaging- Small Gage Line No. Taper a Gage Notch, End to End of per Line Class X Class Y Class Z Plug Gage A′ L Taper Foot A Gage Gage Gage L′ 0.239 0.50200 0.23922 0.00004 0.00007 0.00010 0.20000 0.94 0.048 0.299 0.50200 0.29968 0.00004 0.00007 0.00010 0.25000 1.19 0.048 0.375 0.50200 0.37525 0.00004 0.00007 0.00010 0.31250 1.50 0.048 1 0.59858 0.47500 0.00004 0.00007 0.00010 0.36900 2.13 0.040 2 0.59941 0.70000 0.00004 0.00007 0.00010 0.57200 2.56 0.040 3 0.60235 0.93800 0.00006 0.00009 0.00012 0.77800 3.19 0.040 4 0.62326 1.23100 0.00006 0.00009 0.00012 1.02000 4.06 0.038 1⁄ 4 2 0.62400 1.50000 0.00006 0.00009 0.00012 1.26600 4.50 0.038 5 0.63151 1.74800 0.00008 0.00012 0.00016 1.47500 5.19 0.038 6 0.62565 2.49400 0.00008 0.00012 0.00016 2.11600 7.25 0.038 7 0.62400 3.27000 0.00010 0.00015 0.00020 2.75000 10.00 0.038 200 0.75000 2.00000 0.00008 0.00012 0.00016 1.703 4.75 0.032 250 0.75000 2.50000 0.00008 0.00012 0.00016 2.156 5.50 0.032 300 0.75000 3.00000 0.00010 0.00015 0.00020 2.609 6.25 0.032 350 0.75000 3.50000 0.00010 0.00015 0.00020 3.063 7.00 0.032 400 0.75000 4.00000 0.00010 0.00015 0.00020 3.516 7.75 0.032 450 0.75000 4.50000 0.00010 0.00015 0.00020 3.969 8.50 0.032 500 0.75000 5.00000 0.00013 0.00019 0.00025 4.422 9.25 0.032 600 0.75000 6.00000 0.00013 0.00019 0.00025 5.328 10.75 0.032 800 0.75000 8.00000 0.00016 0.00024 0.00032 7.141 13.75 0.032 1000 0.75000 10.00000 0.00020 0.00030 0.00040 8.953 16.75 0.032 1200 0.75000 12.00000 0.00020 0.00030 0.00040 10.766 19.75 0.032 a The taper per foot and diameter A at gage line are basic dimensions. Dimensions in Column A′ are calculated for reference only. b Tolerances for diameter A are plus for plug gages and minus for ring gages. All dimensions are in inches. The amount of taper deviation for Class X, Class Y, and Class Z gages are the same, respectively, as the amounts shown for tolerances on diameter A. Taper deviation is the permissible allowance from true taper at any point of diameter in the length of the gage. On taper plug gages, this deviation may be applied only in the direction which decreases the rate of taper. On taper ring gages, this deviation may be applied only in the direction which increases the rate of taper. Tolerances on two-decimal dimensions are ±0.010. British Standard Tapers.—British Standard 1660: 1972, “Machine Tapers, Reduction Sleeves, and Extension Sockets,” contains dimensions for self-holding and self-releasing tapers, reduction sleeves, extension sockets, and turret sockets for tools having Morse and 7⁄ metric 5 per cent taper shanks. Adapters for use with 24 tapers and dimensions for spindle noses and tool shanks with self-release tapers and cotter slots are included in this Standard. STANDARD TAPERS 915

Table 8. Dimensions of Morse Taper Sleeves

AB C D EFGH I K L M 9⁄ 5⁄ 1⁄ 7⁄ 3⁄ 1⁄ 3⁄ 21 3 16 0.700 8 4 16 216 0.475 2 16 4 0.213 15⁄ 1⁄ 5⁄ 9⁄ 3⁄ 1⁄ 3⁄ 31 3 16 0.938 4 16 16 216 0.475 2 16 4 0.213 7⁄ 3⁄ 5⁄ 9⁄ 5⁄ 1⁄ 7⁄ 32 4 16 0.938 4 16 16 28 0.700 2 2 8 0.260 7⁄ 1⁄ 15⁄ 5⁄ 3⁄ 1⁄ 3⁄ 41 4 8 1.231 4 32 8 216 0.475 2 16 4 0.213 7⁄ 1⁄ 15⁄ 5⁄ 5⁄ 1⁄ 7⁄ 42 4 8 1.231 4 32 8 28 0.700 2 2 8 0.260 3⁄ 3⁄ 15⁄ 5⁄ 1⁄ 1⁄ 3⁄ 43 5 8 1.231 4 32 8 34 0.938 3 16 116 0.322 1⁄ 1⁄ 5⁄ 3⁄ 3⁄ 1⁄ 3⁄ 51 6 8 1.748 4 8 4 216 0.475 2 16 4 0.213 1⁄ 1⁄ 5⁄ 3⁄ 5⁄ 1⁄ 7⁄ 52 6 8 1.748 4 8 4 28 0.700 2 2 8 0.260 1⁄ 1⁄ 5⁄ 3⁄ 1⁄ 1⁄ 3⁄ 53 6 8 1.748 4 8 4 34 0.938 3 16 116 0.322 5⁄ 3⁄ 5⁄ 3⁄ 1⁄ 7⁄ 1⁄ 54 6 8 1.748 4 8 4 48 1.231 3 8 14 0.478 5⁄ 3⁄ 3⁄ 1⁄ 3⁄ 1⁄ 3⁄ 61 8 8 2.494 8 4 18 216 0.475 2 16 4 0.213 5⁄ 3⁄ 3⁄ 1⁄ 5⁄ 1⁄ 7⁄ 62 8 8 2.494 8 4 18 28 0.700 2 2 8 0.260 5⁄ 3⁄ 3⁄ 1⁄ 1⁄ 1⁄ 3⁄ 63 8 8 2.494 8 4 18 34 0.938 3 16 116 0.322 5⁄ 3⁄ 3⁄ 1⁄ 1⁄ 7⁄ 1⁄ 64 8 8 2.494 8 4 18 48 1.231 3 8 14 0.478 5⁄ 3⁄ 3⁄ 1⁄ 1⁄ 15⁄ 1⁄ 65 8 8 2.494 8 4 18 54 1.748 4 16 12 0.635 5⁄ 3⁄ 1⁄ 3⁄ 1⁄ 1⁄ 3⁄ 7311 8 3.270 8 18 18 34 0.938 3 16 116 0.322 5⁄ 3⁄ 1⁄ 3⁄ 1⁄ 7⁄ 1⁄ 7411 8 3.270 8 18 18 48 1.231 3 8 14 0.478 5⁄ 3⁄ 1⁄ 3⁄ 1⁄ 15⁄ 1⁄ 7511 8 3.270 8 18 18 54 1.748 4 16 12 0.635 1⁄ 1⁄ 1⁄ 3⁄ 3⁄ 3⁄ 7612 2 3.270 1 4 18 18 78 2.494 7 1 4 0.760

Table 9. Morse Taper Sockets — Hole and Shank Sizes

Morse Taper Morse Taper Morse Taper Size Hole ShankSize Hole ShankSize Hole Shank 1 by 2 No. 1 No. 2 2 by 5 No. 2 No. 5 4 by 4 No. 4 No. 4 1 by 3 No. 1 No. 3 3 by 2 No. 3 No. 2 4 by 5 No. 4 No. 5 1 by 4 No. 1 No. 4 3 by 3 No. 3 No. 3 4 by 6 No. 4 No. 6 1 by 5 No. 1 No. 5 3 by 4 No. 3 No. 4 5 by 4 No. 5 No. 4 2 by 3 No. 2 No. 3 3 by 5 No. 3 No. 5 5 by 5 No. 5 No. 5 2 by 4 No. 2 No. 4 4 by 3 No. 4 No. 3 5 by 6 No. 5 No. 6 916 STANDARD TAPERS

Table 10. Brown & Sharpe Taper Shanks

Dia. of Plug Depth, P Keyway Length Width Length Diame- Thick- Plug at from of of of ter of ness of Taper Mill. Small End of Shank Key- Key- Arbor Arbor Arbor Num- per B & Sb Mach. End Spindle Depth waya way Tongue Tongue Tongue ber of Foot Stan- Stan- Taper (inch) DKSLWTdtdard dard Miscell. c 15⁄ …… 15⁄ 3⁄ 3⁄ 3⁄ 1⁄ 1 .50200 .20000 16 16 116 8 .135 16 .170 8 c 3⁄ …… 11⁄ 1⁄ 1⁄ 1⁄ 5⁄ 2 .50200 .25000 1 16 1 64 12 2 .166 4 .220 32 1⁄ …… 15⁄ 7⁄ 5⁄ 5⁄ 3⁄ 1 2 1 32 18 8 .197 16 .282 16 c …… 3⁄ 23⁄ 1⁄ 5⁄ 5⁄ 3⁄ 3 .50200 .31250 1 4 132 28 8 .197 16 .282 16 …… 31⁄ 3⁄ 5⁄ 5⁄ 3⁄ 2 1 32 28 8 .197 16 .282 16 … 1⁄ … 13⁄ 21⁄ 11⁄ 11⁄ 7⁄ 1 4 1 64 132 16 .228 32 .320 32 4 .50240 .35000 11⁄ …… 41⁄ 3⁄ 11⁄ 11⁄ 7⁄ 1 16 1 64 232 16 .228 32 .320 32 … 3⁄ … 11⁄ 3⁄ 3⁄ 3⁄ 1⁄ 1 4 1 16 216 4 .260 8 .420 4 …… 15⁄ 7⁄ 3⁄ 3⁄ 1⁄ 5 .50160 .45000 2 1 16 216 4 .260 8 .420 4 1⁄ …… 1⁄ 9⁄ 3⁄ 3⁄ 1⁄ 2 8 2 16 216 4 .260 8 .420 4 3⁄ …… 19⁄ 7⁄ 7⁄ 7⁄ 9⁄ 6 .50329 .50000 2 8 2 64 28 8 .291 16 .460 32 …… 1⁄ 13⁄ 1⁄ 15⁄ 15⁄ 5⁄ 2 2 232 332 16 .322 32 .560 16 7⁄ …… 25⁄ 13⁄ 15⁄ 15⁄ 5⁄ 7 .50147 .60000 2 8 2 32 332 16 .322 32 .560 16 … … 29⁄ 17⁄ 15⁄ 15⁄ 5⁄ 3 2 32 332 16 .322 32 .560 16 9⁄ …… 29⁄ 1⁄ 1⁄ 11⁄ 8 .50100 .75000 3 16 3 64 48 1.3532 .710 32 … … 7⁄ 5⁄ 1⁄ 9⁄ 3⁄ 4 3 8 48 18 .385 16 .860 8 9 .50085 .90010 1⁄ …… 1⁄ 7⁄ 1⁄ 9⁄ 3⁄ 4 4 4 8 48 18 .385 16 .860 8 …… 27⁄ 23⁄ 5⁄ 21⁄ 7⁄ 5 4 32 532 116 .447 32 1.010 16 … 11⁄ … 17⁄ 13⁄ 5⁄ 21⁄ 7⁄ 10 .51612 1.04465 5 16 5 32 632 116 .447 32 1.010 16 …… 7⁄ 1⁄ 15⁄ 5⁄ 21⁄ 7⁄ 6 32 616 616 116 .447 32 1.010 16 15⁄ …… 25⁄ 21⁄ 5⁄ 21⁄ 7⁄ 5 16 5 32 632 116 .447 32 1.210 16 11 .50100 1.24995 … 3⁄ … 19⁄ 15⁄ 5⁄ 21⁄ 7⁄ 6 4 6 32 732 116 .447 32 1.210 16 1⁄ 1⁄ … 15⁄ 15⁄ 1⁄ 3⁄ 1⁄ 7 8 78 6 16 716 12 .510 4 1.460 2 12 .49973 1.50010 …… 1⁄ ………………… 6 4 3⁄ …… 9⁄ 9⁄ 1⁄ 3⁄ 1⁄ 13 .50020 1.75005 7 4 7 16 816 12 .510 4 1.710 2 1⁄ 1⁄ … 1⁄ 5⁄ 11⁄ 27⁄ 9⁄ 14 .50000 2.00000 8 4 84 8 32 932 116 .572 32 1.960 16 3⁄ …… 17⁄ 21⁄ 11⁄ 27⁄ 9⁄ 15 .5000 2.25000 8 4 8 32 932 116 .572 32 2.210 16 1⁄ …… 1⁄ 7⁄ 15⁄ 5⁄ 16 .50000 2.50000 9 4 9 10 4 18 .635 16 2.450 8 3⁄ …… …… … ………… 17 .50000 2.75000 9 4 1⁄ …… …… … ………… 18 .50000 3.00000 10 4 a Special lengths of keyway are used instead of standard lengths in some places. Standard lengths need not be used when keyway is for driving only and not for admitting key to force out tool. b “B & S Standard” Plug Depths are not used in all cases. c Adopted by American Standards Association. STANDARD TAPERS 917

Table 11. Jarno Taper Shanks

Number Length Length Diameter Diameter Taper of Taper A B C D per foot 1⁄ 2 1 8 1 0.20 0.250 0.600 5⁄ 1⁄ 3 1 8 12 0.30 0.375 0.600 3⁄ 4 2 16 2 0.40 0.500 0.600 11⁄ 1⁄ 5 2 16 22 0.50 0.625 0.600 3⁄ 6 3 16 3 0.60 0.750 0.600 11⁄ 1⁄ 7 3 16 32 0.70 0.875 0.600 3⁄ 8 4 16 4 0.80 1.000 0.600 11⁄ 1⁄ 9 4 16 42 0.90 1.125 0.600 1⁄ 10 5 4 5 1.00 1.250 0.600 3⁄ 1⁄ 11 5 4 52 1.10 1.375 0.600 1⁄ 12 6 4 6 1.20 1.500 0.600 3⁄ 1⁄ 13 6 4 62 1.30 1.625 0.600 1⁄ 14 7 4 7 1.40 1.750 0.600 3⁄ 1⁄ 15 7 4 72 1.50 1.875 0.600 5⁄ 16 8 16 8 1.60 2.000 0.600 13⁄ 1⁄ 17 8 16 82 1.70 2.125 0.600 5⁄ 18 9 16 9 1.80 2.250 0.600 13⁄ 1⁄ 19 9 16 92 1.90 2.375 0.600 5⁄ 20 10 16 10 2.00 2.500 0.600

Tapers for Machine Tool Spindles.—Most lathe spindles have Morse tapers, most milling machine spindles have American Standard tapers, almost all smaller milling machine spindles have R8 tapers, and large vertical milling machine spindles have American Stan- dard tapers. The spindles of drilling machines and the taper shanks of twist drills are made to fit the Morse taper. For lathes, the Morse taper is generally used, but lathes may have the Jarno, Brown & Sharpe, or a special taper. Of 33 lathe manufacturers, 20 use the Morse taper; 5, the Jarno; 3 use special tapers of their own; 2 use modified Morse (longer than the standard but the same taper); 2 use Reed (which is a short Jarno); 1 uses the Brown & Sharpe standard. For grinding machine centers, Jarno, Morse, and Brown & Sharpe tapers are used. Of ten grinding machine manufacturers, 3 use Brown & Sharpe; 3 use Morse; and 4 use Jarno. The Brown & Sharpe taper is used extensively for milling machine and divid- ing head spindles. The standard milling machine spindle adopted in 1927 by the milling machine manufacturers of the National Machine Tool Builders' Association (now The 1⁄ Association for Manufacturing Technology [AMT]), has a taper of 3 2 inches per foot. This comparatively steep taper was adopted to ensure easy release of arbors. 918 STANDARD TAPERS

Table 12. American National Standard Plug and Ring Gages for Steep Machine Tapers ANSI/ASME B5.10-1994

Tolerances for Diameter Ab Diame- Length Overall Taper Diameter ter at Gage Line Length Dia. No. per at Small to of Gage of of Foota Gage Linea Class X Class Y Class Z Enda Small End Body Opening Taper (Basic) A Gage Gage Gage A′ L B C 5 3.500 0.500 0.00004 0.00007 0.00010 0.2995 0.6875 0.81 0.30 10 3.500 0.625 0.00004 0.00007 0.00010 0.3698 0.8750 1.00 0.36 15 3.500 0.750 0.00004 0.00007 0.00010 0.4401 1.0625 1.25 0.44 20 3.500 0.875 0.00006 0.00009 0.00012 0.4922 1.3125 1.50 0.48 25 3.500 1.000 0.00006 0.00009 0.00012 0.5443 1.5625 1.75 0.53 30 3.500 1.250 0.00006 0.00009 0.00012 0.7031 1.8750 2.06 0.70 35 3.500 1.500 0.00006 0.00009 0.00012 0.8438 2.2500 2.44 0.84 40 3.500 1.750 0.00008 0.00012 0.00016 1.0026 2.5625 2.75 1.00 45 3.500 2.250 0.00008 0.00012 0.00016 1.2839 3.3125 3.50 1.00 50 3.500 2.750 0.00010 0.00015 0.00020 1.5833 4.0000 4.25 1.00 55 3.500 3.500 0.00010 0.00015 0.00020 1.9870 5.1875 5.50 1.00 60 3.500 4.250 0.00010 0.00015 0.00020 2.3906 6.3750 6.75 2.00 a The taper per foot and diameter A at gage line are basic dimensions. Dimensions in Column A′ are calculated for reference only. b Tolerances for diameter A are plus for plug gages and minus for ring gages. All dimensions are in inches. The amounts of taper deviation for Class X, Class Y, and Class Z gages are the same, respectively, as the amounts shown for tolerances on diameter A. Taper deviation is the permissible allowance from true taper at any point of diameter in the length of the gage. On taper plug gages, this deviation may be applied only in the direction which decreases the rate of taper. On taper ring gages, this deviation may be applied only in the direction which increases the rate of taper. Tolerances on two-decimal dimensions are ±0.010. STANDARD TAPERS 919

Table 13. Jacobs Tapers and Threads for Drill Chucks and Spindles

Taper Taper Taper Taper Series AB Cper Ft. Series AB Cper Ft. No. 0 0.2500 0.22844 0.43750 0.59145 No. 4 1.1240 1.0372 1.6563 0.62886 No. 1 0.3840 0.33341 0.65625 0.92508 No. 5 1.4130 1.3161 1.8750 0.62010 No. 2 0.5590 0.48764 0.87500 0.97861 No. 6 0.6760 0.6241 1.0000 0.62292 No. 2a 0.5488 0.48764 0.75000 0.97861 No. 33 0.6240 0.5605 1.0000 0.76194 No. 3 0.8110 0.74610 1.21875 0.63898 ……… … … a These dimensions are for the No. 2 “short” taper.

Thread Diameter D Diameter E Dimension F Size Max. Min. Max. Min. Max. Min. 5⁄ 16 –24 0.531 0.516 0.3245 0.3195 0.135 0.115 5⁄ 16 –24 0.633 0.618 0.3245 0.3195 0.135 0.115 3⁄ 8 –24 0.633 0.618 0.385 0.380 0.135 0.115 1⁄ 2 –20 0.860 0.845 0.510 0.505 0.135 0.115 5⁄ 8 –11 1.125 1.110 0.635 0.630 0.166 0.146 5⁄ 8 –16 1.125 1.110 0.635 0.630 0.166 0.146 45⁄ 64 –16 1.250 1.235 0.713 0.708 0.166 0.146 3⁄ 4 –16 1.250 1.235 0.760 0.755 0.166 0.146 1–8 1.437 1.422 1.036 1.026 0.281 0.250 1–10 1.437 1.422 1.036 1.026 0.281 0.250 1⁄ 1 2 –8 1.871 1.851 1.536 1.526 0.343 0.312

Threada G Plug Gage Pitch Dia. Ring Gage Pitch Dia. Size Max MinHb Go Not Go Go Not Go 5⁄ c 16 –24 0.3114 0.3042 0.437 0.2854 0.2902 0.2843 0.2806 3⁄ d 8 –24 0.3739 0.3667 0.562 0.3479 0.3528 0.3468 0.3430 1⁄ 2 –20 0.4987 0.4906 0.562 0.4675 0.4731 0.4662 0.4619 5⁄ 8 –11 0.6234 0.6113 0.687 0.5660 0.5732 0.5644 0.5589 5⁄ 8 –16 0.6236 0.6142 0.687 0.5844 0.5906 0.5830 0.5782 45⁄ 64 –16 0.7016 0.6922 0.687 0.6625 0.6687 0.6610 0.6561 3⁄ 4 –16 0.7485 0.7391 0.687 0.7094 0.7159 0.7079 0.7029 1–8 1.000 0.9848 1.000 0.9188 0.9242 0.9188 0.9134 1–10 1.000 0.9872 1.000 0.9350 0.9395 0.9350 0.9305 1⁄ 1 2 –8 1.500 1.4848 1.000 1.4188 1.4242 1.4188 1.4134 a 1⁄ Except for 1–8, 1–10, 1 2 –8 all threads are now manufactured to the American National Standard Unified Screw Thread System, Internal Class 2B, External Class 2A. Effective date 1976. b 5⁄ 3⁄ Tolerances for dimension H are as follows: 0.030 inch for thread sizes 16 –24 to 4 –16, inclusive 1⁄ and 0.125 inch for thread sizes 1–8 to 1 2 –8, inclusive. c Length for Jacobs 0B5⁄16 chuck is 0.375 inch, length for 1B5⁄16 chuck is 0.437 inch. d Length for Jacobs No. 1BS chuck is 0.437 inch. 5⁄ Usual Chuck Capacities for Different Taper Series Numbers: No. 0 taper, drill diameters, 0– 32 1⁄ 1⁄ 5⁄ 1⁄ 1⁄ 5⁄ 3⁄ 3⁄ 1⁄ inch; No. 1, 0– 4 inch; No. 2, 0– 2 inch; No. 2 “Short,” 0– 16 inch; No. 3, 0– 2 , 8 – 8 , 16 – 4 , or 4 – 13⁄ 1⁄ 3⁄ 3⁄ 1⁄ 1⁄ 16 inch; No. 4, 8 – 4 inch; No. 5, 8 –1; No. 6, 0– 2 inch; No. 33, 0– 2 inch. 5⁄ 1⁄ 3⁄ Usual Chuck Capacities for Different Thread Sizes: Size 16 –24, drill diameters 0– 4 inch; size 8 – 3⁄ 1⁄ 3⁄ 5⁄ 1⁄ 1⁄ 1⁄ 1⁄ 3⁄ 5⁄ 1⁄ 24, drill diameters 0– 8 , 16 – 8 , or 64 – 2 inch; size 2 –20, drill diameters 0– 2 , 16 – 8 , or 64 – 2 inch; 5⁄ 1⁄ 5⁄ 1⁄ 1⁄ 5⁄ 3⁄ 3⁄ 45⁄ size 8 –11, drill diameters 0– 2 inch; size 8 –16, drill diameters 0– 2 , 8– – 8 , or 16 – 4 inch; size 64 1⁄ 3⁄ 1⁄ 3⁄ 3⁄ –16, drill diameters 0– 2 inch; size 4 –16, drill diameters 0– 2 or 16 – 4 . 920 STANDARD TAPERS M H H Z .002 total ′ G X

ANSI B5.18-1972 (R1998)

Slot and key location ° J Keyseat Key tight fit in slot when insert key is used

45 Z ′ F F Preferred

Key Construction ° 45 G – X – B X .0004 See note 4 A gage K .015 .015 Usable threads E M min Max variation from gage line min L Face of column section Z-Z F C Optional Standard steep machine taper 3.500 inch per ft Key Construction G min D Table 1. Essential Dimensions of American National Standard Spindle Noses for Milling Machines X See Note 3 STANDARD TAPERS 921 M Hole Depth Thread for Bolt for of Usable of L Min. in Spindle Arbor Hole Arbor Full Depth of Depth Full 10 8.62 1.25 11 5.50 1.00 13 4.75 0.81 16 2.88 0.62 13 3.88 0.81 – – – – – K ANSI B5.18-1972 (R1998) B5.18-1972 ANSI Holes Size of for Bolt for Threads UNC-2B 0.750 0.625 0.500 0.375 0.500 J 2) Hole 3.500 1.500 Circle 1.0625 1.3125 Radius of Bolt of (Note 2) (Note (Note 1) (Note (Note 1) (Note (Note 1) (Note 2.000(Note 2.000(Note H Keys 2.420 2.414 1.410 1.404 0.660 0.654 0.910 0.904 1.160 1.154 Distance to Driving to fromCenter ′ of G Depth Keyseat Minimum G Key 0.50 0.50 0.50 0.50 0.31 0.31 0.31 0.31 0.38 0.38 Driving Height ofHeight Maximum ′ of F 0.999 1.000 0.999 1.000 0.624 0.625 0.624 0.625 0.749 0.750 Width Keyseat F of Key Width 1.0006 1.0002 1.0006 1.0002 0.6255 0.6252 0.6255 0.6252 0.7505 0.7502 Driving E End to End Spindle Column Minimum Dimension D 1.38 1.50 1.06 0.75 0.66 0.50 0.66 0.62 0.78 0.62 Draw-in Hole for Bolt Min. Clearance 0.010 unless otherwise specified. ± C Dia. Pilot 2.381 2.371 1.568 1.559 0.692 0.685 1.005 0.997 1.286 1.278 Essential Dimensions of American National Standard Spindle Noses for Milling Machines B Dia.of 8.7180 8.7175 5.0618 5.0613 2.7493 2.7488 3.4993 3.4988 3.9993 3.9988 Spindle A (Continued) Holes spaced as shown and located within 0.006 inch diameter of true position. Holes spaced as shown and located within 0.010 inch diameter of true position. Maximum turnout on test plug: Squareness of mounting face measured near mounting bolt hole circle. Gage Taper Dia.of Centrality of keyway with axis of taper 0.002 total at maximum material condition. (0.002 Total indicator variation) Taper: Tolerance on rate of taper to be 0.001 inch per foot applied only in direction which decreases rate of taper. Centrality of solid key with axis of taper 0.002 total at maximum material condition. (0.002 Total indicator variation) — — ′ — All dimensions are given in inches. Tolerances: Two-digit decimal dimensions A F F 1: Note 2: Note 3: Note 4: Note 60 4.250 50 2.750 30 1.250 40 1.750 45 2.250 No. Size 0.0004 at 1 inch projection from gage line. 0.0010 at 12 inch projection from gage line. Table 1. 922 STANDARD TAPERS

Table 2. Essential Dimensions of American National Standard Tool Shanks for Milling Machines ANSI B5.18–1972, R1991

Size of Tap Drill Thread Minimum Minimum Size Gage Size for for Draw-in Length of Depth of No. Dia.of Draw-in Dia.of Bolt Pilot Length Usable Clearance Taper Thread Neck UNC-2B Dia. of Pilot Thread Hole N O P M R S T U 0.422 0.66 0.675 30 1.250 0.500–13 0.81 1.00 2.00 0.432 0.65 0.670 0.531 0.94 0.987 40 1.750 0.625–11 1.00 1.12 2.25 0.541 0.93 0.980 0.656 1.19 1.268 45 2.250 0.750–10 1.00 1.50 2.75 0.666 1.18 1.260 0.875 1.50 1.550 50 2.750 1.000–8 1.00 1.75 3.50 0.885 1.49 1.540 1.109 2.28 2.360 60 4.250 1.250–7 1.75 2.25 4.25 1.119 2.27 2.350

Distance from Distance Rear of Clearance from Gage Flange of Flange Tool Shank Width of Line to Depth Diameter to End from Gage Centerline to Driving Bottom of 60° of Size. of Arbor Diameter Driving Slot Slot of C'bore Center C'bore No. V W X Y Z K L 0.045 0.640 0.635 0.05 0.525 30 2.75 2.50 0.075 0.625 0.645 0.07 0.530 0.045 0.890 0.635 0.05 0.650 40 3.75 3.50 0.075 0.875 0.645 0.07 0.655 0.105 1.140 0.760 0.05 0.775 45 4.38 4.06 0.135 1.125 0.770 0.07 0.780 0.105 1.390 1.010 0.05 1.025 50 5.12 4.75 0.135 1.375 1.020 0.12 1.030 0.105 2.400 1.010 0.05 1.307 60 8.25 7.81 0.135 2.385 1.020 0.12 1.312 All dimensions are given in inches. Tolerances: Two digit decimal dimensions ± 0.010 inch unless otherwise specified. M—Permissible for Class 2B “NoGo” gage to enter five threads before interference. N—Taper tolerance on rate of taper to be 0.001 inch per foot applied only in direction which increases rate of taper. Y—Centrality of drive slot with axis of taper shank 0.004 inch at maximum material condition. (0.004 inch total indicator variation) STANDARD TAPERS 923

Table 3. American National Standard Draw-in Bolt Ends ANSI B5.18–1972, R1991

Length of Length of Usable Thread Size of Thread Size of Thread Size Length of Usable Thread on Large Diam- for Large End for Small End No. Small End at Small End eter UNC-2A UNC-2A A B C M D 30 1.06 0.75 0.75 0.500–13 0.375–16

40 1.25 1.00 1.12 0.625–11 0.500–13

45 1.50 1.12 1.25 0.750–10 0.625–11

50 1.50 1.25 1.38 1.000–8 0.625–11

60 1.75 1.37 2.00 1.250–7 1.000–8

All dimensions are given in inches. Table 4. American National Standard Pilot Lead on Centering Plugs for Flatback Milling Cutters ANSI B5.18-1972 (R1998) 924 STANDARD TAPERS

Table 5. Essential Dimensions for American National Standard Spindle Nose with

Large Flange ANSI B5.18-1972 (R1998) Slot and key location M 2 Usable -X- X .002 Total M

threads ° 45 45 ° K Z American Standard Usable

M 2nd Position Taper 3.500 Inch Per Ft 1 threads X See Note 1 K H .015 2 H .015 J J 1 D min C A 1 gage H1

H2 Max variation from

X .0004 Gage Line See note 2 1st Position Face of Z E Column B

min L min F1 Keyseat

section Z-Z F Key tight fit in slot G′

G1 Drive Key

Distance Clearance Min. from Hole Dim. Height Center to Size Gage Dia. for Spindle Width of Depth Driving No. Diam. of Draw-in End of Driving of Keys of Spindle Pilot Bolt to Driving Key Keyseat First Taper Flange Dia. Min. Column Key Max. Min. Position A B C D E F G G1 H1 8.7180 1.568 1.0006 1.410 50A 2.750 1.06 0.75 0.50 0.50 8.7175 1.559 1.0002 1.404 Distance Radius Depth from of Bolt Size of Full of Center to Hole Threads Depth Usable Driving Circles for of Thread Keys (See Note 3) Bolt Arbor for Size Second Holes Hole in Bolt Width No. Position Inner Outer UNC-2B Spindle Holes of Min. Keyseat H2 J1 J2 K1 K2 L M1 M2 F1 2.420 0.999 50A 2.000 3.500 0.625–11 0.750–10 5.50 1.00 1.25 2.410 1.000 All dimensions are given in inches. Tolerances: Two-digit decimal dimensions ± 0.010 unless otherwise specified. A—Tolerance on rate of taper to be 0.001 inch per foot applied only in direction which decreases rate of taper. F—Centrality of solid key with axis of taper 0.002 inch total at maximum material condition. (0.002 inch Total indicator variation)

F1—Centrality of keyseat with axis of taper 0.002 inch total at maximum material condition. (0.002 inch Total indicator variation) Note 1: Maximum runout on test plug: 0.0004 at 1 inch projection from gage line. 0.0010 at 12 inch projection from gage line. Note 2: Squareness of mounting face measured near mounting bolt hole circle. Note 3: Holes located as shown and within 0.010 inch diameter of true position. STANDARD TAPERS 925 ° when Angle =118 Length of Point Included ° =90 when Angle Length of Point of Included 0.4375 0.219 0.131 0.5625 0.281 0.169 0.39060.4063 0.1950.4219 0.203 0.117 0.2110.4531 0.122 0.4688 0.127 0.2270.4844 0.234 0.136 0.2420.5156 0.141 0.5313 0.145 0.2580.5469 0.266 0.155 0.2730.5781 0.159 0.5938 0.164 0.2890.6094 0.297 0.173 0.3050.6406 0.178 0.6563 0.183 0.3200.6719 0.3280.6875 0.192 0.3360.7188 0.197 0.344 0.202 0.359 0.206 0.216 0.3750 0.188 0.113 0.5000 0.250 0.150 0.6250 0.313 0.188 0.7500 0.375 0.225 Decimal Equivalent

8 64 32 64 64 32 64 2 64 32 64 64 32 64 8 64 32 64 16 32 4 ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ 16 16 ⁄ ⁄ 3 1 5 3 of 7 9 25 13 27 29 15 31 33 17 35 37 19 39 41 21 43 11 23 Dia. Drill ° of Point when Angle =118 Length Included ° =90 when Angle Length of Point Included 0.2813 0.1410.3125 0.084 0.156 0.094 0.2344 0.1170.2656 0.070 0.1330.2969 0.080 0.1480.32810.3438 0.089 0.1640.3594 0.171 0.098 0.180 0.103 0.108 0.2500 0.125 0.075 Decimal Equivalent

64 4 64 64 64 32 64 ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ 32 16 ⁄ ⁄ 1 9 5 15 17 19 21 11 23 Dia. Size or of Drill ° when Angle =118 Length of Point Included ° =90 when Angle Length of Point Included Decimal Equivalent Length of Point on Twist Drills and Centering Tools Centering and Drills Twist on Point of Length of Size Drill ° when Angle =118 Length of Point Included ° =90 when Angle Length of Point Included Decimal Equivalent of 60 0.0400 0.020 0.012 37 0.1040 0.052 0.031 14 0.1820 0.091 0.055 55 0.0520 0.026 0.016 3247 0.1160 0.0785 0.058 0.040 0.035 0.024 9 24 0.1960 0.1520 0.098 0.076 0.059 0.046 1 0.2280 0.114 0.068 5857 0.042056 0.0430 0.021 0.046554 0.02253 0.013 0.023 0.055052 0.013 0.0595 0.014 35 0.028 0.063550 34 0.03049 0.1100 0.017 33 0.032 0.070048 0.1110 0.018 0.055 0.0730 0.1130 0.019 31 0.035 0.056 0.076046 30 0.033 0.037 0.05745 0.1200 0.021 29 0.033 0.038 0.0810 1244 0.1285 0.022 0.034 0.060 0.0820 11 0.1360 0.023 27 0.041 0.065 0.0860 1042 26 0.1890 0.036 0.041 0.06841 0.1440 0.024 25 0.1910 0.039 0.043 0.093540 0.095 0.1470 0.025 8 0.1935 0.041 0.072 0.096039 0.096 0.1495 0.026 7 23 0.047 0.057 0.074 0.098038 0.097 22 6 0.043 0.048 0.1990 0.057 0.075 0.0995 0.1540 0.028 21 0.044 0.049 0.2010 0.058 0.1015 0.1570 0.029 4 0.100 0.045 0.050 0.2040 0.077 0.1590 0.029 3 19 0.101 0.051 0.079 0.060 0.030 2 18 0.102 0.046 0.2090 0.080 0.060 0.1660 0.030 17 0.047 0.2130 0.061 0.1695 16 0.105 0.048 0.2210 0.083 0.1730 15 0.107 0.085 0.063 0.1770 0.111 0.050 0.087 0.064 0.1800 0.051 0.089 0.067 0.052 0.090 0.053 0.054 59 0.0410 0.021 0.012 3651 0.1065 0.0670 0.054 0.034 0.032 0.020 13 2843 0.1850 0.1405 0.0890 0.093 0.070 0.045 0.056 0.042 0.027 5 20 0.2055 0.1610 0.103 0.081 0.062 0.048 Size Drill